Polymers containing amino groups, and their preparation

ABSTRACT

Homopolymers, copolymers and/or block copolymers which are obtained from vinylaromatics and/or dienes, are modified with functional amino groups and contain functional groups of the formula (I) or (II) ##STR1## where N is nitrogen, R 1  and R 2  are each alkyl or aryl, A is an unsubstituted or substituted one-membered carbon bridge, Me is an alkali metal and B is a 2-membered to 12-membered carbon bridge in which at least the members adjacent to the nitrogen atoms consists of --C(R 3 ,R 4 ) radicals, where R 3  and R 4  can be identical or different and are each hydrogen, alkyl, cycloalkyl or aryl, and the more remote members can be not only --C(R 3  R 4 ) radicals but also ether or N-alkyl- or N-arylimino groups, a process for the preparation of the polymers from the corresponding living anionically polymerized polymers, or polymers metallized with an alkali metal, and the coresponding hydrazine derivatives, and the use of the polymers for the preparation of similar polymers possessing functional groups of the general formula (V) or (VI) ##STR2## by reaction with an equivalent amount of water, or of similar polymers possessing the functional groups of the general formula (VII) or (VIII) ##STR3## by reaction with an excess of water.

The present invention relates to homopolymers, copolymers and/or blockcopolymers which are modified with aminofunctional groups and obtainedfrom vinyl aromatics and/or dienes, their preparation from livinganionically polymerized homopolymers, copolymers and/or block copolymersof vinyl aromatics and/or dienes or from polymers of this type whichhave been metallized with an alkali metal, and their use for thepreparation of similar polymers by reaction with water.

Polymers of this type are high molecular weight compounds havingmolecular weights M_(w) of from 500 to 500,000 and containing functionalgroups and/or terminal groups randomly distributed over the polymermolecules and/or at the chain ends.

Polymers obtained from vinyl aromatics and/or dienes and modified withfunctional groups, and their preparation from the corresponding living,anionically polymerized polymers or from the polymers metallized with analkali metal have long been known. For example, polymers containingsecondary amino groups can be obtained according to German Laid-OpenApplication DOS No. 2,003,128 by a method in which high molecular weightorgano-alkali metal compounds are reacted with N-alkyllactams. In aknown process for the preparation of polymeric compounds containing anydesired number of functional groups, polymeric, polyfunctionalorgano-alkali metal compounds are reacted with reactive, low molecularweight compounds, such as carbon dioxide, carbon disulfide,halogen-substituted amines, alkylene oxides or aliphatichalohydrocarbons (cf. U.S. Pat. No. 3,951,931). Processes formetallizing unsaturated polymers and reacting the resulting metallizedpolymer with reactive chemical compounds are also described in U.S. Pat.Nos. 3,781,260 and 3,976,628. FR-A-2 437 417 discloses a process formetallizing certain ethylene terpolymers and reacting the product withan aliphatic lactam, copolymers modified with functional groups beingobtained. British Pat. Nos. 1,173,508 and 2,138,005 too, describepolymers, in particular diene polymers, which are modified withfunctional groups and are formed by reacting the corresponding alkalimetal diene polymers with aliphatic tertiary amines or complexes oftertiary amines with sulfur trioxide. Finally, U.S. Pat. No. 4,015,061discloses polymers which possess terminal bistrialkylsilylamino groups,are obtained from the corresponding metallized polymers andsilicon-amino compounds and can be converted to the correspondingamine-substituted polymers by reaction with water. The synthesis ofpolymers containing primary amino terminal groups by reacting livinganionic polymers with protected aminating reagents, such astrimethylsilylbromoethylamine, is described by A. Hirao et al. inMakromol. Chem., Rapid Commun. 3 (1982), 59-63.

The disadvantage of the known processes for introducing amino groupsinto polymers is that these processes frequently take place withmoderate yield, so that the reaction products contain large amounts ofinert, high molecular weight polymers formed as a result of sidereactions. Furthermore, the amine-modified polymers are not obtained inone step. The polymers possessing terminal amino groups have to beliberated from initially formed intermediates by expensive reactions andpurification steps.

It is an object of the present invention to provide polymers ofvinylaromatics and/or dienes in a reaction which takes place in one wayand with high conversion, the resulting polymers possessing one or moreamino groups or terminal groups. It is a further object of the presentinvention to provide polymers of vinylaromatics and/or dienes, whichpolymers are modified with functional amino groups and are contaminatedonly slightly, if at all, by inert by-products or by the reactive lowmolecular weight compounds. It is a further object of the presentinvention to obtain polymers possessing amino groups by a simple method.

We have found that these objects are achieved by polymers according toclaims 1 to 5 and 7 and 8, by a process for the preparation of thepolymers according to claim 6 and by the use of the polymers accordingto claim 1 for the preparation of polymers according to claims 7 and 8.

Polymers modified with functional amino groups are those which containthe functional groups (I), (II) and (V) to (VIII), both randomlydistributed in the chain and at the chain ends of a macromolecule. Thepolymers preferably possess 1 to 10 functional groups permacro-molecule, depending entirely on the number of living anionic chainends or metallized groups used.

Homopolymers, copolymers and block copolymers of vinylaromatics and/ordienes are the known polymers of this type which can be obtained fromthe corresponding monomers by anionic polymerization, for example withthe aid of organo-alkali metal initiators. Processes of this type aresufficiently well known to make further discussion here unnecessary (cf.for example British Pat. No. 1,444,680 or J. Appl. Polym. Sci. 22(1978), 2007-2913).

Particularly suitable vinylaromatics are styrene, the variousalkylstyrenes and vinylnaphthalene, while suitable dienes are butadiene,isoprene, 2,3-dimethylbutadiene, piperylene, phenylbutadiene and otheranionically polymerizable conjugated C₄ -C₁₂ -dienes. In addition to thehomopolymers, the copolymers and the known block copolymers ofvinylaromatics and dienes are also suitable, and block copolymers orcopolymers having a random distribution of the monomers can be obtained,depending on the choice of initiator and solvent.

The polymers generally have a mean molecular weight (weight averageM_(w)) of from 500 to 500,000, determined by gel permeationchromatography (GPC) and comparison with standardized polymers suitablefor calibration (cf. G. Glockner, Polymercharakterisierung durchFlussigkeitschromatographie, Verlag A. Huthig, Heidelberg, 1982.Measurements are usually carried out in 0.25% strength by weightsolution in tetrahydrofuran at 23° C. and at an average flow rate of 1.2ml/min).

According to the invention, the novel polymers should contain thefunctional groups of the formula (I) or (II) ##STR4## where N isnitrogen, R¹ and R² are each alkyl or aryl, A is an unsubstituted orsubstituted one-membered carbon bridge, Me is an alkali metal and B is a2-membered to 12-membered bridge in which at least the members adjacentto the nitrogen atoms consist of ##STR5## radicals, where R³ and R⁴ canbe identical or different and are each hydrogen, alkyl, cycloalkyl oraryl, and the more remote members can be not only --C(R³, R⁴) radicalsbut also ether or N-alkyl or arylimino groups. Suitable alkali metalsare Li, Na, K, Rb and Cs, in particular Li.

The novel polymers preferably contain on average 1 to 10 of thefunctional groups (I) or (II) in the macromolecule, ie. based on the sumof all macromolecules, a statistical average of 1 to 10 functionalgroups should be present per macromolecule.

Other preferred polymers are those in which R¹ and R² are each C₁ -C₄-alkyl, in particular butyl, and the carbon bridge A is the methylenegroup --CH₂ -- or the dimethylmethylene group --C(CH₃)₂, those in whichthe bridge B consists of three or four unsubstituted or substitutedmethylene groups, in particular --CH₂ CH₂ CH₂ -- or --CH(CH₃)--CH₂CH(CH₃)--, and those in which B consists of two, three or four carbonmembers, of which one or more is methylene and the other two form partof one or more alicyclic or aromatic ring systems. Examples of groups Bwhich are suitable for this purpose are ##STR6##

The novel polymers possessing the functional groups (I) or (II) areprepared by a conventional method, either from the living anionicallypolymerized homopolymers, copolymers and/or block polymers ofvinylaromatics and/or dienes or from polymers of this type which aremetallized with an alkali metal (cf. the literature cited at the outsetand J. M. Malan et al. Chem. Rev. 69 (1969) (5), 693-755). To do this,the monomers are subjected to anionic polymerization at low temperaturesin the presence of an alkali metal or its alkyl or aryl derivative, inparticular in the presence of an alkyl derivative of lithium, such assec-butyllithium, in an inert solvent, such as an aliphatic or aromatichydrocarbon, in particular hexane or cyclohexane, benzene or toluene, orin the presence of tetrahydrofuran. These processes give polymers whichcontain metals bonded to the terminal groups. However, it is alsopossible to prepare homopolymers, copolymers and/or block copolymers ofvinylaromatics and/or dienes and to carry out metallization subsequentlywith an alkali metal or one of its derivatives. Such metallized polymerscontain the organometallic groups randomly distributed along the chain.

According to the invention, the above organometallic polymers arereacted with hydrazine derivatives of the general formula (III) or (IV)##STR7## where R¹, R², A and B have the meanings stated at the outset,in the presence of a solvent. Preferred solvents are aliphatic oraromatic hydrocarbons, such as hexane, cyclohexane, benzene, toluene,etc. The reaction is preferably carried out in the absence of water andin an inert atmosphere, eg. under pure nitrogen. In the reaction, theratio of the number of equivalents of the hydrazine derivative to thenumber of equivalents of alkali metal is advantageously from 1:1 to1.5:1. The reaction is carried out at from -70° to 100° C., preferablyat from 0° to 60° C. During the reaction with the organometallic groupsof the polymers, the N--N bond is cleaved, the polymer radicalundergoing addition at one nitrogen and the metal, eg. lithium, at theother nitrogen.

Suitable compounds (III) and (IV) are those in which R¹ and R² are eachalkyl or aryl, A is an unsubstituted or substituted one-membered carbonbridge, and B is a 2-membered to 12-membered bridge, of which at leastthe members adjacent to the N atoms consist of --(CR³, R⁴) radicals,where R³ and R⁴ can be identical or different and are each hydrogen,alkyl, cycloalkyl or aryl and the more remote members can be not only--(CR³, R⁴) radicals but also ether or N-alkyl or N-arylimino groups.

Preferred radicals R¹ and R² and bridges A and B are disclosed in thesubclaims 3, 4 and 5 at the outset in the description. Lithium is thepreferred alkali metal.

Examples of suitable hydrazine derivatives of the general formulae (III)and (IV) are: ##STR8## Compound (b) is particularly suitable.

This list is not complete and is not intended to impose any limit.Further individual compounds and the preparation of hydrazinederivatives of this type have been described by, for example, R. Ohme etal., Chem. Ber. 99 (1966), 2104-2109 and by E. Schmitz and K.Schinkowsky, Chem. Ber. 97 (1964), 49.

The reaction with the hydrazine derivatives takes place quantitativelyand very rapidly. The fact that they need not be used in excess or maybe required in only slight excess is an advantage, since the convertedpolymers are hardly contaminated by unconverted hydrazine derivatives.The living polymer solutions, which have an intense orange redcoloration when the chain end consists of styrene or its substitutionproducts, can, for example, be titrated with the hydrazine derivativeuntil the color vanishes.

The novel polymers possessing the functional groups (I) and (II) havethe advantage that they can be used for the preparation of similarpolymers containing the functional groups of the general formulae (V)and (VI) ##STR9## if they are reacted with an amount of water equivalentto the alkali metal, the latter being replaced by hydrogen. Thisreaction takes place spontaneously when water is added, lithiumhydroxide also being formed.

Another advantage of the novel polymers possessing the functional groups(I) and (II) is that they can be converted to the polymers possessingfunctional groups of the general formulae (VII) and (VIII) ##STR10## bymeans of an excess of water, the bridge A being eliminated.

This reaction too takes place spontaneously in some cases. It is alsopossible to treat the novel polymers with water-containing acids, eg.concentrated hydrochloric acid or 80% strengths by weight acetic acid,at from 40° to 100° C., the bridge A being eliminated. A polymerpossessing primary or secondary amino groups is formed, depending on thehydrazine derivative used:

The Examples which follow illustrate the invention.

PREPARATION OF THE HYDRAZINE DERIVATIVES USED1,5-Diazabicyclo[3.1.0]hexane

37.2 g (1/2 mole) of 1,3-propylenediamine and 250 cm³ of 2N NaOH aremixed with 50 cm³ of 30% strength by weight formalin solution in a 2 lflask with cooling, in such a way that the temperature does not exceed5° C. Thereafter, 274 cm³ of chlorine bleach solution (160 g of freechlorine/liter) are mixed in, while stirring very thoroughly, so thatthe temperature does not exceed 5° C. The solution is evaporated downunder reduced pressure at ≦35° C. to about half its original volume, theprecipitated salt is filtered off and the mother liquor is extractedexhaustively with 5 times 200 cm³ of methylene chloride. The combinedextracts are dried with solid KOH, the methylene chloride is strippedoff under reduced pressure at about 35° C. and the1,5-diazabicyclo[3.1.0]hexane is distilled off under 7 mbar.

B.p. (7 mbar)=47°-52° C.; yield=22.5 g (53.6% of theory).

Content of (in % by weight)

    ______________________________________                                               C     H           N                                                    ______________________________________                                        Found    56.1%   9.7%        33.5%                                            Theory   57.4%   9.52%       33.33%                                                                              for C.sub.4 H.sub.8 N.sub.2                ______________________________________                                    

1,2-Dibutyldiaziridine

The method described in Chem. Ber. 99 (1966), 2105 to 2109 is used.

6,6-Dimethyl-1,5-diazabicyclo[3.1.0]hexane

37.2 g (1/2 mole) of 1,3-propylenediamine and 250 cm³ of 2N NaOH aremixed with 29 g of acetone at 5° C., and 274 cm³ of chlorine bleachsolution (160 g of active chlorine/liter) are added dropwise at 5° C.,while cooling. The solution is extracted with 3 times 200 cm³ methylenechloride, the extracts are dried with solid KOH, the solvent is expelledso that the temperature in the bottom does not exceed 40° C., and theend product is distilled off under 0.3 mbar.

B.p. (0.3 mbar)=40° C.; yield=38.5 g (69% of theory).

Content of (in % by weight)

    ______________________________________                                               C     H          N                                                     ______________________________________                                        Theory   64.3%   10.7%      25%   for C.sub.6 H.sub.12 N.sub.2                Found    64.1%   10.9%      24.9%                                             ______________________________________                                    

6,6-Pentamethylene-1,5-diazabicyclo[3.1.0]hexane

The preparation is carried out using the method employed for6,6-dimethyl-1,5-diazabicyclo[3.1.0]hexane, except that 49 g (1/2 mole)of cyclohexanone were used instead of acetone.

B.p. (0.8 mbar)=87°-89° C.; yield=34.9 g (45% of theory).

    ______________________________________                                                    C     H       N                                                   ______________________________________                                        Found (% by weight)                                                                         70.5    10.7    18.6                                            Theory (% by weight)                                                                        71.1    10.5    18.4 for C.sub.9 H.sub.16 N.sub.2               ______________________________________                                    

EXAMPLE 1

1000 cm³ of cyclohexane and 104 g (1 mole) of purified styrene areintroduced into a 2 liter three-necked flask which has been washed undervery pure nitrogen with a solution of sec-butyllithium in cyclohexane,is provided with a stirrer and a thermometer and is closed with a rubbermembrane.

A 1.4 molar solution of sec-butyllithium in cyclohexane is introducedinto the thoroughly stirred styrene solution at 50° C. with an injectionsyringe until a permanent pale orange coloration is produced.Immediately thereafter, a further 21 millimoles of sec-butyllithium areadded. The solution, which is then intense orange, becomes warmer. After1 hour at 70° C., polymerization is complete. The solution is titratedwith a 50% strength by weight solution of 1,5-diazabicyclo[3.1.0]hexanein toluene, this procedure being carried out through the rubber membraneby means of an injection syringe. When 3.7 cm³ of solution has beenadded, the orange color vanishes. The polymer is precipitated by pouringthe solution into 5 l of ethanol, while stirring thoroughly. The productis filtered off and dried, and the following analytical data aredetermined for the snow-white polystyrene powder: M_(w) =5000,determined by GPC calibrated using a general-purpose polystyrene whichhas a narrow distribution. M_(w) /M_(n) =1.02, where M_(n) is the numberaverage molecular weight, determined by GPC. M_(w) /M_(n) is a measureof the width of the molecular weight distribution.

Basic nitrogen determined by potentiometric titration with perchloricacid in a chlorobenzene/glacial acetic acid mixture: 0.58% by weight.Total nitrogen determined by the Kjeldahl method: 0.6% by weight.

10 g of the polystyrene prepared in this manner are dissolved in 1000cm³ of toluene, and the solution is kept together with 100 cm³ of 90%strength by weight glacial acetic acid for 2 hours at 90° C. Hydrolysisresults in elimination of the methylene bridge. Potentiometric titrationgives a basic nitrogen content of 0.5% by weight.

EXAMPLE 2

A polystyrene is prepared in the same manner as in Example 1, exceptthat termination is effected with a 1,2-dibutyldiaziridine. The polymerhas the following properties:

M_(w) : 5300 (GPC method)

M_(w) /M_(n) =1.03

Basic nitrogen: 0.57% by weight

Total nitrogen: 0.6% by weight

After hydrolysis with glacial acetic acid/H₂ O in toluene, the totalnitrogen is found to have decreased to 0.35% by weight, while basicnitrogen is determined as 0.25% by weight.

EXAMPLE 3

1000 cm³ of toluene and 1 mole (104 g ) of styrene are introduced, underinert conditions, into a flask which has been cleaned under nitrogen bywashing with butyl-lithium solution and is provided with a stirrer, athermometer, a dropping funnel and a rubber cap. A fresh solution of23.0 g of active sodium in 1000 cm³ of tetrahydrofuran and 500 g ofα-methylstyrene is prepared by a conventional method, and 28 cm³ of thissolution are added rapidly to the above solution at 20° C. from thedropping funnel, while stirring thoroughly. The reaction beginsimmediately, and the contents of the flask warm up to 57° C. in thecourse of 1 minute. The virtually black solution is then titrated with a50% strength by weight solution of 1,5-diazabicyclo[3.1.0]hexane intoluene through the rubber membrane using an injection syringe, untilthe color vanishes. 4.7 cm³ (28 millimoles) of1,5-diazabicyclo[3.1.0]hexane solution are required. The followinganalytical data are obtained for the polymer.

M_(w) from GPC: 7600

M_(w) /M_(n) =1.2

Total nitrogen by the Kjeldahl method: 0.8% by weight

Basic nitrogen by potentiometric titration: 0.7% by weight.

The analytical data show that a polystyrene possessing a total of 4amino groups at both ends has been formed.

EXAMPLE 4

In order to prepare a 2-block copolymer consisting of 17% by weight ofstyrene and 83% by weight of butadiene and possessing terminal diaminogroups, a 6 l reactor provided with a stirrer, a thermometer, a refluxcondenser, a rubber membrane and a heating jacket is cleaned by boilingcyclohexane containing 2 cm³ of sec-butyllithium in the reactor undervery pure nitrogen. After this solution has been discharged, the reactoris charged with 3000 cm³ of cyclohexane and 0.9 mole (93.6 g) ofstyrene. A solution of sec-butyllithium is metered in with the aid of aninjection syringe at 40° C. until a pale orange coloration indicatesthat all impurities have been consumed. Thereafter, 12 millimoles ofsec-butyllithium are added and polymerization of the styrene iscompleted in the couse of 1 hour at 65° C. 10.2 moles of butadiene whichhas been purified by distilling off butyllithium are then run in alittle at a time at this temperature. 1 hour after the feed has ended, 2cm³ of styrene are added using a syringe. The solution, which isvirtually colorless during the polymerization of the butadiene, becomesorange after a further hour at 65° C. The solution is then titrated byadding 1,5-diazabicyclo[3.1.0]hexane (50% strength by weight solution intoluene) from a calibrated injection syringe until the color vanishes.1.85 cm³ (11 millimoles or 0.924 g) of the solution are required.

An M_(w) of 55,000 is determined by GPC. The nitrogen content determinedby the Kjeldahl method is 0.047% by weight (theoretical content 0.051).

EXAMPLE 5

In the apparatus described in Example 4, 540 g of isoprene (purifiedover Ca hydride) are polymerized with about 8 millimoles ofsec-butyllithium in 3000 cm³ of cyclohexane. When the polymerization iscomplete, 2 cm³ of styrene are added. After a further hour, the solutionis titrated with 1.68 cm³ of a 50% strength by weight1,5-diazabicyclo[3.1.0]hexane solution until the color vanishes.Molecular weight M_(w) of the polyisoprene, determined by GPC: 60,000

Nitrogen content by the Kjeldahl method: 0.05% by weight (theoreticalcontent 0.047% by weight)

I claim:
 1. A homopolymer, copolymer or block copolymer obtained from avinylaromatic and/or a diene, and modified with functional amino groups,which contains functional groups of the formula (I) or (II) ##STR12##where N is nitrogen, R¹ and R² are each alkyl or aryl, A is anunsubstituted or substituted one-membered carbon bridge, Me is an alkalimetal and B is a 2-membered to 12-membered bridge in which at least themembers adjacent to the nitrogen atoms consist of --C(R³, R⁴) radicals,where R³ and R⁴ can be identical or different and are each hydrogen,alkyl, cycloalkyl or aryl, and the more remote members can be not only--C(R³, R⁴) radicals but also ether or N-alkyl- or N-arylimino groups.2. A polymer as defined in claim 1, which contains on average from 1 to10 of the functional groups (I) or (III) per macromolecule.
 3. A polymeras defined in claim 1, wherein R¹ and R² are each C₁ -C₄ -alkyl and A isa methylene or dimethylmethylene bridge.
 4. A polymer as defined inclaim 1, wherein B is a bridge composed of three or four unsubstitutedor alkyl-substituted methylene groups.
 5. A polymer as defined in claim1, wherein B consists of 2, 3 or 4 carbon members, one or more of whichis methylene and the other two form part of one or more alicyclic oraromatic ring systems.
 6. A polymer as defined in claim 1, wherein thepolymer contains functional amino groups of the formula (II).